New composite mixed adsorbents for the removal of acetic acid by adsorption from aqueous solutions a comparative study

The ability of flyash-activated carbon (AC) - prepared from raw materials such as wood, ricehusk, coconut shell, groundnut shell and bamboo dust and commercial activated carbon (CAC) to adsorb acetic acid (AA) from water has been studied. The percentage of AA adsorbed increased with decrease in initial concentration of AA and particle size of the adsorbent and increased with the increase in contact time and adsorbent dosage. Flyash blended with wood carbon was found to have the maximum sorption potential. The adsorption process followed a first order kinetics and the data was modelled with Freundlich and Langmuir adsorption isotherms. Natarajan and Khalaf, Lagergren, Bhattacharya and Venkobachar and intraparticle diffusion equations were found applicable. From a comparative account of the adsorptive capacity of various flyash blends it was obvious that the flyash-AC blends show a significant affinity and capacity compared to CAC in the removal of acetic acid from water. There seems to be good scope for the use of flyash blends in place of commercial activated carbon - as low-cost adsorbents alternatives to CAC, for the removal of carboxylic acids, in general, and for the removal of acetic acid in particular.